Blocking phone number and txt messages from that number.

Blocking phone number and txt messages from that number.

A friend and I need to block a number from a person who is harrassing us both. How can you block a number so that person cannot text you or call you?

With my old carrier I just hit 0## and the number was blocked. One person said that ATT charges 4.99 to block a number. Another said their was an app you had to download. Can any ATT forum manger address this issue.